The present invention generally relates to semiconductor integrated circuits, and more particularly, to the structure and formation of liner structures that create insulation and diffusion barriers of a tungsten metal contact.
An integrated circuit (IC) generally includes a semiconductor substrate in which a number of device regions are formed by diffusion or ion implantation of suitable dopants. This substrate usually involves a passivating and an insulating layer required to form different device regions. The total thickness of these layers is usually less than one micron. Openings through these layers (called vias or contact holes) allow electrical contact to be made selectively to the underlying device regions. A conducting material is used to fill these holes, which then make contact to semiconductor devices.